1. Technical Field
The present invention relates to a permanent magnet electric rotating machine and an electromotive vehicle using a permanent magnet electric rotating machine and in particularly to a permanent magnet electric rotating machine in which permanent magnets are used as a magnetic flux generating means and an electromotive vehicle such as an electric vehicle which uses the permanent magnet electric rotating machine.
2. Prior Art
Up to now as one kind of an electric rotating machine, a permanent magnet electric rotating machine has been used, in which permanent magnets of the permanent magnet electric rotating machine are used as a magnetic field generating means for a rotor.
As a conventional permanent magnet electric rotating machine, there is a known surface magnet structure permanent magnet electric rotating machine, wherein plural permanent magnets of the permanent magnet electric rotating machine are arranged in parallel and fixed on a surface of a rotor and further adjacent permanent magnets are arranged to have a reversed polarity at a peripheral direction.
However, in the above stated surface magnet structure permanent magnet electric rotating machine, during a high speed rotation there is a possibility of the permanent magnet peeling off due to centrifugal force.
A permanent magnet rotor having a permanent magnet embedding structure permanent magnet electric rotating machine is disclosed in Japanese patent laid-open publication No. Hei 5-76,146. Namely, in the above stated permanent magnet rotor, permanent magnets are inserted in and fixed to holes, such holes extend into an interior portion of the rotor in an axial direction.
Further, so as to aim to simplify a structure for a case in which the rotor having the permanent magnet embedding structure of the permanent magnet electric rotating machine is performed to carry out a skew structure, such a permanent magnet structure of the permanent magnet electric rotating machine is disclosed in Japanese patent laid-open publication No. Hei 5-236,687. Namely, in this permanent magnet structure permanent magnet electric rotating machine, a space is formed from an end face of each of the permanent magnets which are installed in an interior portion of a rotor to an outer periphery of the rotor.
However, in the above stated prior art, there is a problem in which an obtaining of a reluctant torque by auxiliary magnetic poles and a reduction in a cogging torque or a torque pulsation are not incompatible. Hereinafter, in this specification, the torque pulsation indicates one combining both the reluctant torque and the cogging torque.
In the permanent magnet embedding structure permanent magnet electric rotating machine, utilizing the rotor member provided between the adjacent permanent magnets as the auxiliary magnetic pole, a composite vector of an armature magnetomotive force of a stator is controlled to direct toward a side of a rotation direction but not to direct toward a central position direction of the auxiliary magnetic pole, as a result, the reluctant torque can be obtained.
This reluctant torque is added to a main torque generated by the permanent magnets and the entire torque of the permanent magnet electric rotating machine can be increased. Therefore, the efficiency of the permanent magnet embedding structure permanent magnet electric rotating machine can be increased.
On the other hand, in the conventional permanent magnet electric rotating machine, since the permanent magnets always generate a magnetic flux regardless of the existence of an electric power supply, the rotor can always receive a force. The force is one which corresponds to a positional relationship between the permanent magnet and a stator""s salient pole portion and during the rotation time the above stated force changes in a pulsed manner. This pulsating force appears as the torque pulsation.
This torque pulsation obstructs a smooth rotation of the rotor, thus causing a problem in which a stable operation of the permanent magnet electric rotating machine cannot be obtained.
In the permanent magnet rotor of the permanent magnet electric rotating machine shown in Japanese patent laid-open publication No. Hei 5-76,146, since the rotor has the auxiliary magnetic poles, it is possible to obtain the reluctant torque. However, since a distance formed between the permanent magnet and the auxiliary magnetic pole is minute in the periphery direction, an abrupt change in a magnet flux density distribution appears in the minute distance portion, accordingly the torque pulsation arises.
On the other hand, in the permanent magnet electric rotating machine shown in Japanese patent laid-open publication No. Hei 5-236,687, the space is formed between the adjacent permanent magnets. In this space, an adherence property fill-up member comprised of a non-magnetic body is located.
Accordingly, the magnet flux density distribution between the adjacent permanent magnets is muted, such that it hardly generates the cogging torque or the torque pulsation. However, the above stated space or the fill-up member does not work as the auxiliary magnetic pole, therefore the reluctant torque can not be obtained.
An object of the present invention is to provide a permanent magnet electric rotating machine and an electromotive vehicle using a permanent magnet electric rotating machine wherein a torque pulsation can be restrained by obtaining a reluctant torque according to auxiliary magnetic poles.
According to the present invention, a permanent magnet electric rotating machine comprises a stator obtained by a winding on a stator iron core, plural permanent magnet insertion holes for forming magnetic pole piece portions at a side of the stator through auxiliary magnetic pole portions, and a rotor embedding plural permanent magnets in the permanent magnet insertion holes. The rotor is arranged adjacent to the stator with a rotation air gap.
A magnetic gap is provided between at least one of the permanent magnets and at least one of the auxiliary magnetic pole portions which is adjacent to at least one of the permanent magnets in a peripheral direction.
The magnetic gap moderates the change ln the magnetic flux density distribution in the peripheral direction between the permanent magnet and the auxiliary magnetic pole portion, accordingly the torquexe2x80x94pulsation can be decreased.
Therefore, the magnetic gap can be formed merely by the space or by the arrangement or the filling-up of the non-magnetic material.
Further, this magnetic gap can be formed at both ends of the permanent magnets and this magnetic gap can be formed at one end of the peripheral direction of the permanent magnet complying with a request of the rotation direction of the permanent magnet electric rotating machine and a use for applying the permanent magnet electric rotating machine.
However, due to the provision of the above described magnetic gap at the peripheral direction end portion of the permanent magnet, there is a possibility that the positioning of the permanent magnet becomes unstable during the high speed rotation, etc.
For the above stated reasons, according to the present invention, an indented portion is provided at a bottom portion of the permanent magnet, and on the indented portion the permanent magnet is arranged and installed in a stable manner. According to the present invention, a nonmagnetic material member is arranged in the magnetic gap.
Further, since the magnetic gap is enough to moderate the magnetic flux density distribution against the stator, by varying the dimension or the width (space) of the magnetic gap, it is possible to assist the functions of the auxiliary magnetic pole portion.
According to the present invention, a peripheral direction width of the magnetic gap at a face of the stator side (an outer peripheral portion of the stator) is formed larger than a peripheral direction width of the magnetic gap at a face of an anti-stator side (an inner peripheral portion of the stator).
According to the present invention, a peripheral direction cross-section of the magnetic gap is a triangular shape. Therefore, it is possible to circulate the magnetic flux of the auxiliary magnetic pole portions around the permanent magnets, as a result the large reluctance torque of the permanent magnet electric rotating machine can be obtained.
According to the present invention, the magnetic pole piece portion is connected to the auxiliary magnetic pole portion through a bridge portion, and a stator side surface and a magnetic gap side surface of the bridge portion are formed substantially in parallel. The bridge portion is formed to extend vertically toward an inclined face of the magnetic gap.
Therefore, it is possible to restrain the magnetic flux leakage from the permanent magnets and the member of the stator side of the magnetic gap to the auxiliary magnetic pole portions.
Further, according to the present invention, the bridge portion is formed to extend vertically toward an inclined face of the magnetic gap, accordingly the centrifugal force given on the permanent magnet can be supported according to the tensile force of the bridge portion, as a result a permanent magnet electric rotating machine capable of higher speed rotation can be obtained.
According to the present invention, a permanent magnet electric rotating machine comprises a stator having a winding on a stator iron core, plural permanent magnet insertion holes for forming magnetic pole piece portions at a side of the stator through auxiliary magnetic pole portions, and a rotor embedded plural permanent magnets in the permanent magnet insertion holes, the rotor being arranged with respect to the stator with a rotation air gap. A magnetic gap is provided between at least one magnetic piece portion and at least one auxiliary magnetic pole portion.
The above stated magnetic gap can moderate the magnetic flux density distribution at the peripheral direction of the rotor between the permanent magnet and the auxiliary magnetic pole portion.
According to the present invention, the magnetic gap contacts a peripheral direction end portion of a face of a stator side of the permanent magnet. The magnetic gap extends toward an inner side of the permanent magnet.
According to the present invention, the magnetic gap extends with a rectangular shape toward an inner side of the permanent magnet. Therefore, it is possible to restrain the magnetic flux from leaking from the face of the stator side of the permanent magnet to the auxiliary magnetic pole portion.
According to the present invention, a permanent magnet electric rotating machine comprises a stator having a winding on a stator iron core, plural permanent magnet insertion holes for forming magnetic pole piece portions at a side of the stator side through auxiliary magnetic pole portions, and a rotor embedded plural permanent magnets in the permanent magnet insertion holes, the rotor being arranged with respect to the stator with a rotation air gap.
A magnetic gap is provided between at least one magnetic piece portion and at least one auxiliary magnetic pole portion, and the magnetic pole piece portion is fixed to the auxiliary magnetic pole portion through a non-magnetic magnetic pole piece supporting member.
According to the present invention, the magnetic pole piece supporting member has a U-shape and the magnetic pole piece supporting member is inserted from both axis of the rotor iron core. Therefore, the centrifugal force of the permanent magnet given on the magnetic pole piece portion can be supported according to the auxiliary magnetic pole portion.
According to the present invention, a permanent magnet electric rotating machine comprises a stator having a winding on a stator iron core, plural permanent magnet insertion holes for forming magnetic pole piece portions at a side of the stator through auxiliary magnetic pole portions, and a rotor embedded plural permanent magnets in the permanent magnet insertion holes, the rotor being arranged with respect to the stator with a rotation air gap.
A magnetic gap is provided between at least one magnetic piece portion and at least one auxiliary magnetic pole portion, a permanent magnet supporting member is arranged between the magnetic pole piece portion and the permanent magnet and the permanent magnet supporting member is assembled according to a magnetic material member and a nonmagnetic material member.
The magnetic material of the permanent magnet supporting member is arranged between the magnetic pole piece portion and the permanent magnet, and the non-magnetic material member of the permanent magnet supporting member is engaged with the magnetic pole piece portion. Therefore, the supporting force against the centrifugal force acting on the permanent magnet can be increased.
According to the present invention, a non-magnetic material member is arranged in the magnetic gap. Therefore, the supporting force against the centrifugal force given on the permanent magnet can be increased.
According to the present invention, a peripheral direction width of the permanent magnet is smaller than a peripheral direction width of the auxiliary magnetic pole portion. Therefore, the centrifugal force acting on the permanent magnet can be effectively lessened.
According to the present invention, an electromotive vehicle is driven by a permanent magnet electric rotating machine. Therefore, the electromotive vehicle having a small cogging torque and a stable drive apparatus can be provided.
The permanent magnet electric rotating machine according to the present invention can be applied to a generator and an electric motor, an inner rotor type and an outer rotor type permanent magnet electric rotating machine, a rotary type and a linear type permanent magnet electric rotating machine, a concentric winding stator structure and a salient winding stator structure permanent magnet electric rotating machine.
The present invention does not depend on the shape of the permanent magnet, therefore the permanent magnet having a rectangular body, an arc shape, and a trapezoid shape. etc. can be applied and similar effects can be obtained.